The survival of fetal and bone marrow monocyte-derived alveolar macrophages is promoted by CD44 and its interaction with hyaluronan.

Alveolar macrophages maintain lung homeostasis by performing important roles in immunosurveillance and lung surfactant catabolism. They express high levels of CD44 and are one of the few macrophage populations that constitutively bind hyaluronan, a ligand for CD44 and component of pericellular and extracellular matrices. Using adoptive transfer experiments and a mouse model of inflammation, we found that alveolar macrophages are initially depleted after an inflammatory insult then rapidly self-renew and return to original numbers after the resolution phase. Monocytes recruited to an inflamed lung differentiate and contribute to the alveolar macrophage pool, but this occurs over a much slower time frame than alveolar macrophage self-renewal. CD44 expression on both fetal and bone marrow-derived alveolar macrophages promoted their survival and provided a competitive advantage over CD44-deficient alveolar macrophages at homeostasis and after inflammation. CD44-mediated hyaluronan binding was induced by the alveolar environment, and this interaction promoted alveolar macrophage survival both ex vivo and in vivo. Without CD44, alveolar macrophages lacked a hyaluronan coat, were more susceptible to death, and were present at lower numbers in the alveolar space. This demonstrates a new role for CD44 and hyaluronan in promoting alveolar macrophage survival.

CD45 regulates GM-CSF, retinoic acid and T-cell homing in intestinal inflammation.

CD45 is a leukocyte-specific tyrosine phosphatase important for T-cell development, and as a result, CD45-/- mice have substantially reduced numbers of T cells. Here we show that, upon dextran sodium sulfate (DSS)-induced colitis, CD45-/- mice have equivalent intestinal pathology and T-cell numbers in their colon as C57BL/6 mice and show enhanced weight loss. CD45-/- mice have a greater percentage of α4ß7+ T cells prior to and after colitis and an increased percentage of T cells producing inflammatory cytokines in the inflamed colon, suggesting that CD45-/- effector T cells preferentially home to the intestine. In DSS-induced colitis in CD45RAG-/- mice lacking an adaptive immune system, CD45 was required for optimal granulocyte-macrophage colony-stimulating factor (GM-CSF) and retinoic acid (RA) production by innate immune cells. Addition of CD45+/+ T cells led to greater weight loss in the RAG-/- mice compared with CD45RAG-/- mice that correlated with reduced α4ß7+ T cells and lower recruitment to the colon of CD45RAG-/- mice in DSS-induced colitis. Addition of exogenous GM-CSF to CD45RAG-/- mice rescued RA production, increased colonic T-cell numbers, and increased weight loss. This demonstrates opposing effects of CD45 in innate and adaptive immune cells in proinflammatory responses and the expression of the gut-homing molecule, α4ß7.

Does the perception of psychosocial factors increase the risk of pesticide exposure among seasonal Hispanic farmworkers?

BACKGROUND: Migrant farmworkers are prone to several psychosocial stressors. OBJECTIVE: To investigate the effect of perceived psychosocial factors on pesticide exposure among seasonal migrant Hispanic farmworkers in North Carolina, USA. METHODS: A cross-sectional interview survey of 187 seasonal migrant farmworkers of Mexican descent, identified from labor camps located in rural counties in North Carolina, was conducted using nonprobability purposive sampling approach. Multivariable ordinal logistic regression analysis was used to determine the relationship between perceived control over the harmful effects of pesticide exposure, lack of social support, and the impact of anxiety on perception of pesticide exposure. RESULTS: More than 20% (n=39) of farmworkers reported frequent or constant contact with pesticides while working in the fields. More than 68% of farmworkers reported they believe they have control over avoiding harmful effects of pesticide exposure; the odds of pesticide exposure were 55% lower in this group (adjusted OR: 0.45; 95% CI: 0.22-0.91). No significant relationship was observed between farmworkers perception of lack of social support and presence of anxiety with odds of on-field pesticide exposure. CONCLUSION: The study results suggest that perception of control is an important predictor of reduced pesticide exposure among seasonal migrant farmworkers.

Fluid balance and conventional and novel biomarkers of acute kidney injury in cardiovascular surgery.

AIM: Fluid balance (FB) is an emerging predictor of acute kidney injury (AKI). We investigated the comparative utility of FB with conventional and novel biomarkers to predict AKI in cardiovascular surgery patients. METHODS: Data collected in a prospective, observational study designed to investigate the relationship between FB and AKI in an academic medical center were utilized for analyses. FB, routine clinical parameters, conventional and novel biomarkers in 100 consecutive cardiovascular surgery patients was analyzed. RESULTS: Each variable studied was divided into quartiles and the lowest quartile served as the referent quartile. The adjusted OR for AKI for the highest vs. lowest quartile of FB was 4.98 (CI95%1.38-24.10, P=0.046), serum creatinine (SCr) 11.54 (CI95% 1.37-97.18, P=0.024), urine NGAL 2.76 (CI95% 0.48-15.93, P=0.255) and IL-18 2.31 (CI95% 0.41-13.16, P=0.346, and serum MCP-1 4.93 (CI95% 0.81-30.09, P=0.084) and TNF-alpha 15.59 (CI95% 1.19-204.19, P=0.036). Comparison of ROC curves demonstrated that the diagnostic performance of FB and SCr to predict AKI were comparable, as were FB with urine NGAL and IL-18 and serum MCP-1 and TNF-alpha.. While there was a graded relationship with the risk for AKI according to quartiles for FB, SCr and serum TNF-alpha, the remaining biomarkers including urine NGAL were not independent predictors of AKI. CONCLUSION: At 24 hours postoperatively, the performance of FB to predict AKI was comparable to that of preoperative conventional and postoperative 24-hour novel biomarkers.

Association between workplace and housing conditions and use of pesticide safety practices and personal protective equipment among North Carolina farmworkers in 2010.

BACKGROUND: There are inconsistencies about the effects of farmworker housing and workplace conditions and use of self-protective behavior practices and personal protective equipment (PPE). OBJECTIVE: To investigate the association between workplace and housing conditions and farmworker use of pesticide safety practices and PPE. METHODS: This study was conducted in 4 counties in North Carolina, USA, from July to October, 2010, during the agricultural growing season. Farmworkers working in agriculture aged 18 to 62 (n = 187) were administered a structured questionnaire to collect self-reported measures on housing and workplace conditions. Use of pesticide safety and PPE were examined by asking questions about wearing gloves, wearing socks, and wearing a hat. Chi-square and multiple logistic regression analyses were used for statistical analyses. RESULTS: Farmworkers reporting availability of enough hot and cold water for bathing and doing laundry were 13.6 times more likely to use pesticide safety practices (adjusted OR: 13.6, 95% CI: 1.4-135.4), whereas, those who reported that soap for handwashing was always or usually available while doing agricultural work were 7.8 times more likely to use pesticide safety practices (adjusted OR: 7.8, 95% CI: 3.3-18.5). Farmworkers that reported access to water to wash their hands with while performing agricultural work were more likely to use PPE (adjusted OR: 3.4, 95% CI: 1.3-9.2). CONCLUSION: Some migrant farmworker labor camps are not supplying acceptable housing conditions such as 1 handwashing sink per 6 people (n = 10, 5.4%). Use of pesticide safety practices and PPE is greater when farmers provide decontamination supplies. Improvement of housing and workplace conditions are crucial to increase use of pesticide safety practices and PPE.

Occupational exposures and asthma among nursing professionals.

OBJECTIVES: To identify occupational exposure risk factors associated with the development of new-onset asthma in nurses. METHODS: A cross-sectional survey was administered to a sample of licensed Texas nurses (response rate 70%) and compared to three other healthcare professional groups. Nursing professionals were defined based on self-reported longest held job. Outcome variables were physician-diagnosed new-onset asthma after entry into the healthcare profession and symptoms associated with bronchial hyper-responsiveness (BHR). Occupational exposures were ascertained through a job-exposure matrix, grouped into four categories: cleaning-related tasks, use of powdered latex gloves, administration of aerosolised medications, and tasks involving adhesive compounds, glues and/or solvents. RESULTS: After adjustment for age, sex, ethnicity, atopy, smoking, body mass index and seniority, reported asthma was significantly greater among nursing professionals involved in medical instrument cleaning (OR = 1.67, 95% CI 1.06 to 2.62) and exposure to general cleaning products and disinfectants (OR = 1.72, 95% CI 1.00 to 2.94). Use of powdered latex gloves during 1992-2000 was associated with 1.6 times (95% CI 1.01 to 2.50) the odds of reported asthma. In univariate analysis, exposure to adhesives, glues and/or solvents was associated with a twofold increase in the odds of reported asthma, but not after adjustment for covariates. Similarly, the odds of BHR-related symptoms were significantly greater among nursing professionals exposed to general cleaning products and disinfectants (OR = 1.57, 95% CI 1.11 to 2.21) and adhesives, glues and/or solvents used in patient care (OR = 1.51, 95% CI 1.08 to 2.12). CONCLUSION: Among nursing professionals, workplace exposures to cleaning products and disinfectants increase the risk of new-onset asthma.

Validation of an asthma questionnaire for use in healthcare workers.

BACKGROUND: Previous studies have described increased occurrence of asthma among healthcare workers, but to our knowledge there are no validated survey questionnaires with which to study this occupational group. AIMS: To develop, validate, and refine a new survey instrument on asthma for use in epidemiological studies of healthcare workers. METHODS: An initial draft questionnaire, designed by a multidisciplinary team, used previously validated questions where possible; the occupational exposure section was developed by updating health services specific chemical lists through hospital walk-through surveys and review of material safety data sheets. A cross-sectional validation study was conducted in 118 non-smoking subjects, who also underwent bronchial challenge testing, an interview with an industrial hygienist, and measurement of specific IgE antibodies to common aeroallergens. RESULTS: The final version consisted of 43 main questions in four sections. Time to completion of the questionnaire ranged from 13 to 25 minutes. Test-retest reliability of asthma and allergy items ranged from 75% to 94%, and internal consistency for these items was excellent (Cronbach's alpha > or = 0.86). Against methacholine challenge, an eight item combination of asthma related symptoms had a sensitivity of 71% and specificity of 70%; against a physician diagnosis of asthma, this same combination showed a sensitivity of 79% and specificity of 98%. Agreement between self-reported exposures and industrial hygienist review was similar to previous studies and only moderate, indicating the need to incorporate more reliable methods of exposure assessment. Against the aerollergen panel, the best combinations of sensitivity and specificity were obtained for a history of allergies to dust, dust mite, and animals. CONCLUSIONS: Initial evaluation of this new questionnaire indicates good validity and reliability, and further field testing and cross-validation in a larger healthcare worker population is in progress. The need for development of more reliable occupational exposure assessment methods that go beyond self-report is underscored.

Prevalence and correlates of paediatric asthma and wheezing in a largely rural USA population.

OBJECTIVE: The prevalence of asthma among children has been increasing in the United States and it is estimated that there are approximately 5 million children with asthma. This cross-sectional survey sought to estimate the prevalence of asthma and asthma symptoms and potential risk factors among children aged 16 and younger, in a largely rural population in the USA. METHODS: This study was a telephone survey of 1500 households in the South Plains/Panhandle region of Texas. Parents of children were interviewed with a response rate of 64%. Having been diagnosed with asthma by a physician and a report of wheezing in the last 12 months were used as dependent variables in multivariate logistic regressions with several sociodemographic and environmental factors as potential confounders. RESULTS: The age-adjusted prevalence of asthma and wheezing among children were approximately 15 and 18%, respectively. The prevalence of asthma was highest (20%) among children aged 11-16 (P < 0.001). Living in urban areas was associated significantly with asthma and wheezing. Non-Hispanic blacks reported significantly increased odds of asthma in their children (adjusted odds ratio (OR) = 2.04, 95%CI 1.02-4.08), whereas Mexican-Americans reported significantly reduced odds of asthma (adjusted OR = 0.48, 95%CI 0.29-0.78) and wheezing (adjusted OR = 0.58, 95%CI 0.37-0.89) in their children. The odds of asthma (adjusted OR = 1.78, 95%CI 1.09-2.92) and wheezing (adjusted OR = 2.45, 95%CI 1.52-3.95) was highest among children in the highest body mass index quartile. No significant association with pet ownership and exposure to second-hand smoke with asthma and wheezing was observed in this study. CONCLUSION: Urban residence, non-Hispanic black and Mexican-American race/ethnicity, and being overweight were significantly associated with the increased risk of asthma and/or wheezing.

Prevalence and risk factors of asthma and wheezing among US adults: an analysis of the NHANES III data.

The prevalence of asthma has been on the increase in the USA and worldwide. To understand the worsening epidemiological trends of asthma, this study analysed the data from the third National Health and Nutrition Examination Survey (NHANES III) to determine the prevalence and risk factors for asthma and wheezing among US adults. This analysis used data from 18,825 US adults aged > or = 20 yrs who had participated in the NHANES III project. After excluding subjects with physician-diagnosed emphysema, a total of 18,393 subjects were included in the final analysis. The prevalence of current asthma (asthma) was 4.5% and the prevalence of wheezing in the previous 12 months (wheezing) was 16.4%. Mexican-Americans exhibited the lowest prevalence of asthma when compared with other race/ethnic groups. Multiple logistic regression analysis showed that Mexican-Americans were less likely to report asthma when compared to non-Hispanic whites. Low education level, female sex, current and past smoking status, pet ownership, lifetime diagnosis of physician-diagnosed hay fever and obesity were all significantly associated with asthma and/or wheezing. No significant effect of indoor air pollutants, as derived from the use of household heating/cooking appliances, on asthma and wheezing was observed in this study. In conclusion, this study observed racial/ethnic differences in the prevalence of asthma and wheezing and identified several important risk factors that may contribute to development and/or exacerbation of asthma and wheezing. Contrary to earlier reports, the proxy measures of indoor air pollution used in this study were not found to be associated with increased risk of asthma and wheezing.

Prevalence and risk factors of work related asthma by industry among United States workers: data from the third national health and nutrition examination survey (1988-94).

OBJECTIVES: To estimate the prevalence of work related asthma and work related wheezing in United States workers. To identify high risk industries that could be targeted for future intervention. To determine the population attributable risk of work related asthma and work related wheezing. METHODS: The third national health and nutrition examination survey, 1988-1994 (NHANES III) was analyzed to determine the prevalence of work related asthma and wheezing and to identify initially defined industries at risk among United States workers aged 20 and older. Separate logistic models were developed with work related asthma and work related wheezing as outcomes. Work related asthma was defined as affirmative response to questions on self reported physician diagnosed asthma and work related symptoms of rhinitis, conjunctivitis, and asthma. Work related wheezing was defined as affirmative response to questions on self reported wheezing or whistling in the chest in the previous 12 months and work related symptoms of rhinitis, conjunctivitis, and asthma. All analyses were adjusted for age, sex, smoking, and atopy. RESULTS: The prevalence of work related asthma was 3.70% (95% confidence interval (95% CI) 2.88 to 4.52) and the prevalence of work related wheezing was 11.46% (95% CI 9.87 to 13.05). The main industries identified at risk of work related asthma and wheeze included the entertainment industry; agriculture, forestry, and fishing; construction; electrical machinery; repair services; and lodging places. The population attributable risk for work related asthma was 36.5% and work related wheezing was 28.5%. CONCLUSIONS: The findings provide impetus for further research and actions by public health professionals which prioritise occupational asthma on the public health agenda. Future intervention strategies need to be developed for effective control and prevention of asthma in the workplace.

Prevalence and correlates of smoking on the roof of the world.

OBJECTIVE: To determine the prevalence and correlates of cigarette smoking among adults in high mountain rural areas of northern Pakistan. DESIGN: Cross sectional survey. PARTICIPANTS: A sample of 4203 adults (aged 18 years and over) were selected by stratified random sampling from 16 villages. MAIN OUTCOME MEASURE: Self reported smoking prevalence; age of smoking initiation; daily cigarette consumption and association between current smoking and sociodemographic variables, use of snuff, wine, body mass index, blood pressure, family history of stroke, and hypertension. RESULTS: 614/1406 men (43.7%) and 154/2797 (5.5%) women reported smoking cigarettes. The age standardised prevalence of smoking was 40.5% for men and 6.3% for women. Men were more likely (odds ratio (OR) 6.5, 95% confidence interval (CI) 4.75 to 8.79) to be smokers. Smokers were more likely to use snuff (OR 1.39, 95% CI 1.12 to 1.73), drink wine (OR 3.47, 95% CI 2.81 to 4.29), and were more likely to work as farmers (OR 1.55, 95% CI 1.05 to 2.29) or shopkeepers (OR 2.63, 95% CI 1.67 to 4.14). Individuals with college level education and with desirable body mass index were less likely to smoke (OR 0.55, 95% CI 0.35 to 0.87; OR 0.74, 95% CI 0.57 to 0.96). CONCLUSION: Cigarette smoking is a major public health problem in this high mountain community of Pakistan, particularly among the male population, the majority of whom begin to smoke quite early in life. A comprehensive tobacco control effort incorporated into the existing community based health infrastructure is needed.

Preparation, characterization, and X-ray crystal structures of helical and syndiotactic zinc-based coordination polymers.

The reactions of (facac)2Zn.2H2O (facac = 1,1,1,5,5,5-hexafluoroacetylacetonate) with 2,5-bis(4-ethynylpyridyl)furan (1) and 1,2-bis(4-ethynylpyridyl)benzene (2) yield, upon crystallization, coordination polymers. The former polymer, ((facac)2Zn.1)n, has an isotactic, helical structure in the solid state [monoclinic space group P2(1)/n; a = 11.0374(3) A, b = 24.2179(10) A, c = 14.3970(4) A, beta = 92.880(2) degrees; Z = 4]. The latter polymer, ((facac)2Zn.2)n, adopts a syndiotactic structure in the solid state [monoclinic space group P2(1)/n; a = 9.1344(1) A, b = 21.7985(5) A, c = 16.0322(4) A, beta = 99.6680(11) degrees; Z = 4]. The solution structures of the corresponding oligomers have been studied by low-temperature 1H and 19F NMR spectroscopy. Chiral polymers were prepared using the fragment [(+)-tfc]2Zn ((+)-tfc = 3-((trifluoromethyl)hydroxymethylene)-(+)-camphorate). A linear, zigzag structure was found for ([(+)-tfc]2Zn.1)n [triclinic space group P1; a = 7.4833(2) A, b = 14.1563(5) A, c = 21.21230(5) A, alpha = 78.4440(15) degrees, beta = 81.5644(15) degrees, gamma = 76.4976(13) degrees; Z = 1]. Reaction with tris(4-pyridyl)methanol (3) yielded a homochiral, helical polymer, ([(+)-tfc]2Zn.3)n [monoclinic space group C2; a = 25.0633(12) A, b = 11.8768(7) A, c = 17.1205(9) A, alpha = 90 degrees, beta = 117.954(3) degrees, gamma = 90 degrees; Z = 4].

Antibody response to heat shock proteins and histopathology in mice infected with Trypanosoma cruzi and maintained at elevated temperature.

Highly susceptible C3HeB/FeJ mice survive an otherwise lethal infection with a Brazil strain of Trypanosoma cruzi when held at an elevated environmental temperature of 36 C. The body temperature of these mice has been shown to increase 3-4 C to levels typical of a febrile response. In the present study, the synthesis of parasite heat shock proteins (hsp60, hsp70, and hsp90) was shown to be enhanced at a temperature of 39 C and the results of immunoprecipitation analysis indicated that parasite HSPs are highly immunogenic in T. cruzi-infected mice maintained at 36 C or room temperature (RT). Differences in the histopathology of cardiac and skeletal muscle in C3HeB/FeJ mice maintained at RT or 36 C at different times postinfection also were investigated in this study. The lower numbers of circulating parasites observed in mice maintained at 36 C were correlated with lower levels of tissue parasitism, inflammation, and tissue destruction. Finally, the transfer of infected mice from RT to an environment of 36 C at various times during infection was shown to increase the survival rate of infected mice and also resulted in a dramatic reduction in parasitemia levels. In light of the growing evidence for a beneficial effect of elevated temperature during experimental Chagas' disease, further studies seem warranted to determine if hyperthermia or fever therapy might also be beneficial in the treatment of humans infected with T. cruzi.